Chlorinating apparatus



March 14, 1933. w M H L 1,901,524

CHLORINATING APPARATUS Original Filed Sept. 13, 1929 Patented Mar. 14,1933 UNITED STATES PATENT OFFICE WILHELM MOSGHEL, OI BITTERFELD,GERMANY, ASSIGNOR, BY MESNE ASSIGNMENTS, 'I'O MAGNESIUM DEVELOPMENTCORPORATION, A CORPORATION OF DELAWARE CHLORINATING APPARATUS Originalapplication filed September 13, 1929, Serial N0. 392,462,- and inGermany October t, 1928. Divided i and this application filed December2, 1930. Serial No. 499,606.

This invention relates to chlorinating apparatus to be used inconnection with processes for the preparation of anhydrous metalchlorides,'and is a divisional application of my application Ser. No.392,462 filed September 13, 1929 and entitled Process for producinganhydrous magnesium chloride?.

Various processes are known for the conversion of metal oxides andsimilar compounds such as carbonates or silicates into the correspondingmolten anh drous chlorides by means of chlorine or chlorinating gases inthe presence of carbon and at temperatures about or above the meltingpointcof such chlorides. However, most of these processes are attendedwith the drawback that the conversion proceeds excessively slowly andeven remains incomplete in the end. This is due to the fact that thereactive surface of the solid bodies to be acted upon by the chlorine,viz. mixtureseither briquetted and coked or not-of the metal oxide withvarious forms of carbon is small, and that the molten chloride initiallyformed on the surface of such solid bodies envelops the latter whilecombining with the remaining unreacted substance so as to form a crustor paste which prevents further access of the chlorine to the interiorof said bodies. But even if such molten chloride be removed, it isalways contaminated with certain amounts of unconverted oxide or carbonand thus cannot yield a pure final product.

Similar. conditions prevail when it is a question of producing moltenanhydrous metal chlorides from metal chlorides still containing water ofcrystallization in a chlorinating atmosphere vin the presence of carbon.When using the term chlorination or chlorinating in the following, alsodehydrating processes of this kind are considered.

An object of the present invention therefore is to provide an apparatuswhich will enable, chlorination to proceed smoothly and completely byallowing the impure molten chloride formed on the surface of the solidstarting material to flow oif immediately, and subsequently to convertsaid impure chloride into a final product of excellent purity.

The invention will be described with par ticular reference to theproduction of pure anhydrous magnesium chloride from a crude mixture ofpieces of magnesite and pieces of carbon; but it will be understood thatit is by no means limited to the employment of starting material of thiskind and when in this form, but is equally applicable to the use ofcompounds of other metals forming molten chlorides, as well as to thetreatment of briapparatus which provides for passing chlorine in uniformdistribution into a loose mixture of pieces of magnesitc and pieces ofcarb011, preferably wood charcoal or peat charcoal (or loosely arrangedbriquettes of an intimate coked mixture of magnesite and such carbon, asthe case may be) at temperatures closely about or above the meltingpoint of magnesium chloride, and for immediately removing the fusedmagnesium chloride formed in a direction substantially opposed to thatof the ascending current of chlorine so as to convert any traces ofoxide still remaining in such molten chloride, while continuallymaintaining the most suitable temperatures in the different stages'ofthe reaction.

For this purpose, the mixture of pieces of magnesite and pieces of woodcharcoal is placed on an electrically heated pervious layer of carbonand is there caused to react at a temperature of 700900 (1., withchlorine which is, for the purpose of uniform-distribution, best passedthrough this layer of carbon from below. The resulting magnesiumchloride fuses immediately, runs through the heated layer of carbon, andcollects in its lower portion from whence it can be withdrawn from timeto time in' the fused state and in an anhydrous and oxide-freecondition. The reaction itself furnishes sufficient heat to maintain thetemperature necessary for the reaction and it isconsequently sufficientonce and for all merely to preheat the reaction material to thenecessary temperature. This preheating is effected by introducingsuitable heating elements into the reaction material. Preferably, thelower portion of the current lead, passed from above through thereaction material, for electrically heating the layer of carbon is inthe form of a heating element, e. g., a carbon rod or carbon tube; ifnecessary, a plurality of current leads (three phase current heating)can be employed.

The pervious heated layer ofcarbon situated beneath'the reactionmaterial and acting as a sieve serves to enable the liquid magnesiumchloride formed to be run off rapidly. It is therefore advantageouslyformed of rather coarse pieces of a mechanically resistant carbon thatis electrically conductive and chemically inertfor example,- fragmentsof hard carbon electrodes.

In order more clearly to understand the invention reference is made tothe accompanying drawing which shows diagrammat ically and by way ofexample one embodiment of apparatus suitable for carrying out theinvention.

In said drawing A indicates a closed shaft which is lined withfire-proof brickwork a, b, 0. The shaft is filled for about one third ofthe way up with coarse-grained'carbon 7: which constitutes the perviouslayer of carbon. The electric current is supplied through the leads dand e. The upper lead d has its lower portion 'in theform of a tube onfor the purpose of effecting, owing to increased resistance, the heatingup of the reaction. material 2', a mixture of magnesite and pieces ofreactive charcoal, lying upon the layer is. The chlorine is passed intothe-layer k through the pipe 7 and the reaction material is fed in at g.An opening it serves for the removal of the waste gases. The finishedmagnesium chloride collects in the bottom portions of the layer is andis from time to time run off at l in the liquid state.

I claim:

1. A chlorinating apparatus comprising a closed shaft provided with afire-proof lining, a tapping hole in the proximity of the bottom ofsaidshaft, at least one gas inlet in the lower part of said shaft butabove said tapping hole, a layer of coarse pieces of me.- chanicallyresistant and chemically inert carbon in the bottom of said shaftextending upwards somewhat beyond said gas inlet, a feeding aperture andagas outlet in the ceiling of said shaft, a free reaction space in theupper part of said shaft, an electrode in the bottom of said shaft andin contact with said carbon layer and at least one rodshaped electrodevertically inserted in the ceiling of said shaft and extending throughsaid free reaction space so as to contact with said carbon layer. I

2. A chlorinating apparatus comprising a closed shaft provided witha'fire-proof lining, a tapping hole in the proximity of the bottom ofsaid shaft, at least one gas inlet said free reaction space so as tocontact with,

said carbon layer, the lower portion of said ro d-shaped electrodehaving the form of a tu e.

3. A chlorinating apparatus for countercurrent chlorination comprising aclosed shaft provided with a fireproof lining, a layer of pieces ofmechanically resistant carbon, which is chemically inert to the reactingmaterials, disposed in the bottom of the shaft and extending upwardlytherein for a substantial portion of its length, the upper surface ofsaid carbon layer forming withthe walls of said shaft a reaction space,an electrode disposed in the bottomof said shaft and contacting saidcarbon layer, another electrode disposed in the upper portion of saidshaft and contacting the upper surface of said carbon layer, meansdisposed in said shaft walls for supplying a gaseous reactant throughsaid carbon layer, means disposed in said shaft wall for supplyingnon-gaseous reactant directed intosaid reaction space and upon saidcarbon layer and means for withdrawing from the bottom of said shaft theproducts of the reaction.

4:. A chlorinating apparatus for counter current chlorination comprisinga closed shaft provided with a fireproof lining, a-

layer of pieces of mechanically resistant carbon, which is chemicallyinert to the reacting materials, disposed in the bottom of the shaft andextending upwardly therein for a substantial portion of its length, theupper surface of said carbon layer forming with the walls of said shafta reaction space, means for initially starting a reaction comprising anelectrode disposed in the bottom of said shaft and contacting saidcarbon layer and another electrode disposed in the upper portion of saidshaft and contacting the upper surface of said carbon layer, meansdisposed in said shaft walls for supplying a gaseous reactant throughsaid carbon layer, means disposed in said shaft wall for supplyingnon-gaseous reactant directed into said reaction space and upon saidcarbon layer and means for withdrawing from y the bottom of said shaftthe products of the reaction? 5 A chlorinating apparatus forcountercurrent chlorination comprising a closed shaft, a gas inlet inthe lower portion of said shaft, a layer of mechanically resistant andchemically inert carbon in said shaft e1:- tendin u wardsbeyond said gasinlet, an electro le disposed in thebottom of said shaft 5 in contactwith the carbon layer, and an electrode extending into the top of saidshaft into contact with said carbon layer, said top electrode beingtubular in form adjacent its lower end whereb its resistance isincreased.

6. A chlorinating ap aratus comprising upper and lower electro esarranged in contact with a mechanically resistant and chemically inertcarbon layer, atleast one of said electrodes being reduced in crosssection over a portion of its length, whereby its resistance isincreased.

In testimony whereof .I have hereunto set my hand. v TWILHELM MOSCHEL.

